<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jan 8, 2016 at 1:34 PM, Adrian Prantl <span dir="ltr"><<a href="mailto:aprantl@apple.com" target="_blank">aprantl@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><span class=""><blockquote type="cite"><div>On Jan 8, 2016, at 1:31 PM, David Blaikie <<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 6, 2016 at 11:22 AM, Adrian Prantl via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: adrian<br>
Date: Wed Jan  6 13:22:19 2016<br>
New Revision: 256962<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=256962&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=256962&view=rev</a><br>
Log:<br>
Module debugging: Defer emitting tag types until their definition<br>
was visited and all decls have been merged.<br>
<br>
We only get a single chance to emit the types for virtual classes because<br>
CGDebugInfo::completeRequiredType() categorically doesn't complete them.<br></blockquote><div><br></div><div>Not sure I'm following this comment. Could you explain this in other words/detail?<br><br>If we visit a declaration we shouldn't do anything, right? (no point putting declarations in the modules debug info, unless it's needed for something else?) & then when we see the definition we'd build the debug info for it?</div></div></div></div></div></blockquote><div><br></div></span><div>Yes. Your statement pretty much summarizes this commit :-)</div></div></div></blockquote><div><br></div><div>Then I'm still confused - were we emitting type declarations in modules prior to this change?<br><br>Perhaps a test case for a lone declaration (with no follow up definition) would be in order, then?</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><span class="HOEnZb"><font color="#888888"><div><br></div><div>-- adrian</div></font></span><div><div class="h5"><br><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Modified:<br>
    cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp<br>
    cfe/trunk/test/Modules/Inputs/DebugCXX.h<br>
    cfe/trunk/test/Modules/ModuleDebugInfo.cpp<br>
<br>
Modified: cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp?rev=256962&r1=256961&r2=256962&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp?rev=256962&r1=256961&r2=256962&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp (original)<br>
+++ cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp Wed Jan  6 13:22:19 2016<br>
@@ -59,8 +59,10 @@ class PCHContainerGenerator : public AST<br>
   struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {<br>
     clang::CodeGen::CGDebugInfo &DI;<br>
     ASTContext &Ctx;<br>
-    DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)<br>
-        : DI(DI), Ctx(Ctx) {}<br>
+    bool SkipTagDecls;<br>
+    DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx,<br>
+                     bool SkipTagDecls)<br>
+        : DI(DI), Ctx(Ctx), SkipTagDecls(SkipTagDecls) {}<br>
<br>
     /// Determine whether this type can be represented in DWARF.<br>
     static bool CanRepresent(const Type *Ty) {<br>
@@ -75,6 +77,12 @@ class PCHContainerGenerator : public AST<br>
     }<br>
<br>
     bool VisitTypeDecl(TypeDecl *D) {<br>
+      // TagDecls may be deferred until after all decls have been merged and we<br>
+      // know the complete type. Pure forward declarations will be skipped, but<br>
+      // they don't need to be emitted into the module anyway.<br>
+      if (SkipTagDecls && isa<TagDecl>(D))<br>
+          return true;<br>
+<br>
       QualType QualTy = Ctx.getTypeDeclType(D);<br>
       if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))<br>
         DI.getOrCreateStandaloneType(QualTy, D->getLocation());<br>
@@ -165,7 +173,7 @@ public:<br>
     // Collect debug info for all decls in this group.<br>
     for (auto *I : D)<br>
       if (!I->isFromASTFile()) {<br>
-        DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);<br>
+        DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx, true);<br>
         DTV.TraverseDecl(I);<br>
       }<br>
     return true;<br>
@@ -179,6 +187,11 @@ public:<br>
     if (Diags.hasErrorOccurred())<br>
       return;<br>
<br>
+    if (D->isFromASTFile())<br>
+      return;<br>
+<br>
+    DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx, false);<br>
+    DTV.TraverseDecl(D);<br>
     Builder->UpdateCompletedType(D);<br>
   }<br>
<br>
<br>
Modified: cfe/trunk/test/Modules/Inputs/DebugCXX.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/DebugCXX.h?rev=256962&r1=256961&r2=256962&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/DebugCXX.h?rev=256962&r1=256961&r2=256962&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/test/Modules/Inputs/DebugCXX.h (original)<br>
+++ cfe/trunk/test/Modules/Inputs/DebugCXX.h Wed Jan  6 13:22:19 2016<br>
@@ -50,3 +50,9 @@ namespace DebugCXX {<br>
   typedef A<void> B;<br>
   void foo(B) {}<br>
 }<br>
+<br>
+// Virtual class with a forward declaration.<br>
+class FwdVirtual;<br>
+class FwdVirtual {<br>
+  virtual ~FwdVirtual() {}<br>
+};<br>
<br>
Modified: cfe/trunk/test/Modules/ModuleDebugInfo.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/ModuleDebugInfo.cpp?rev=256962&r1=256961&r2=256962&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/ModuleDebugInfo.cpp?rev=256962&r1=256961&r2=256962&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/test/Modules/ModuleDebugInfo.cpp (original)<br>
+++ cfe/trunk/test/Modules/ModuleDebugInfo.cpp Wed Jan  6 13:22:19 2016<br>
@@ -7,13 +7,11 @@<br>
 // RUN: rm -rf %t<br>
 // RUN: %clang_cc1 -triple %itanium_abi_triple -x objective-c++ -std=c++11 -debug-info-kind=limited -fmodules -fmodule-format=obj -fimplicit-module-maps -DMODULES -fmodules-cache-path=%t %s -I %S/Inputs -I %t -emit-llvm -o %t.ll -mllvm -debug-only=pchcontainer &>%t-mod.ll<br>
 // RUN: cat %t-mod.ll | FileCheck %s<br>
-// RUN: cat %t-mod.ll | FileCheck --check-prefix=CHECK-NEG %s<br>
 // RUN: cat %t-mod.ll | FileCheck --check-prefix=CHECK-DWO %s<br>
<br>
 // PCH:<br>
 // RUN: %clang_cc1 -triple %itanium_abi_triple -x c++ -std=c++11 -emit-pch -fmodule-format=obj -I %S/Inputs -o %t.pch %S/Inputs/DebugCXX.h -mllvm -debug-only=pchcontainer &>%t-pch.ll<br>
 // RUN: cat %t-pch.ll | FileCheck %s<br>
-// RUN: cat %t-pch.ll | FileCheck --check-prefix=CHECK-NEG %s<br>
<br>
 #ifdef MODULES<br>
 @import DebugCXX;<br>
@@ -23,22 +21,32 @@<br>
 // CHECK-SAME:                    isOptimized: false,<br>
 // CHECK-SAME-NOT:                splitDebugFilename:<br>
 // CHECK-DWO:                     dwoId:<br>
+<br>
 // CHECK: !DICompositeType(tag: DW_TAG_enumeration_type, name: "Enum"<br>
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX4EnumE")<br>
 // CHECK: !DINamespace(name: "DebugCXX"<br>
+<br>
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "Struct"<br>
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX6StructE")<br>
+<br>
 // CHECK: !DICompositeType(tag: DW_TAG_class_type,<br>
 // CHECK-SAME:             name: "Template<int, DebugCXX::traits<int> >"<br>
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX8TemplateIiNS_6traitsIiEEEE")<br>
+<br>
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "A<void>"<br>
+// CHECK-SAME:             identifier: "_ZTSN8DebugCXX1AIJvEEE")<br>
+<br>
 // CHECK: !DICompositeType(tag: DW_TAG_class_type,<br>
 // CHECK-SAME:             name: "Template<float, DebugCXX::traits<float> >"<br>
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX8TemplateIfNS_6traitsIfEEEE")<br>
-// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "A<void>"<br>
-// CHECK-SAME:             identifier: "_ZTSN8DebugCXX1AIJvEEE")<br>
+<br>
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "FwdVirtual"<br>
+// CHECK-SAME:             elements:<br>
+// CHECK-SAME:             identifier: "_ZTS10FwdVirtual")<br>
+// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "_vptr$FwdVirtual"<br>
+<br>
 // CHECK: !DIDerivedType(tag: DW_TAG_typedef, name: "FloatInstatiation"<br>
 // no mangled name here yet.<br>
+<br>
 // CHECK: !DIDerivedType(tag: DW_TAG_typedef, name: "B",<br>
 // no mangled name here yet.<br>
-<br>
-// CHECK-NEG-NOT: "_ZTSN8DebugCXX8TemplateIlNS_6traitsIlEEEE"<br>
<br>
<br>
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</blockquote></div><br></div></div>
</div></blockquote></div></div></div><br></div></blockquote></div><br></div></div>